The WNT-less wonder: WNT-independent β-catenin signaling

beta-catenin is known as an Armadillo protein that regulates gene expression following WNT pathway activation. However, WNT-independent pathways also activate beta-catenin. During the establishment of the melanocyte lineage, beta-catenin plays an important role. In the context of physiopathology, beta-catenin is activated genetically or transiently in various cancers, including melanoma, where it can be found in the nucleus of tumors. In this review, we discuss alternative pathways that activate beta-catenin independent of WNTs and highlight what is known regarding these pathways in melanoma. We also discuss the role of beta-catenin as a transcriptional regulator in various cell types, with emphasis on the different transcription factors it associates with independent of WNT induction. Finally, the role of WNT-independent beta-catenin in melanocyte development and melanomagenesis is also discussed.